Study on the effects of combined processing of micro‐pulverization and extrusion on the physicochemical properties of oat bran

The utilization rate of oat bran was improved and wastage of resources was reduced using the micro-pulverization technology combined with extrusion in processing oat bran. The effects of micro-pulverization and extrusion treatment on the structure, color, physical and chemical properties, functional properties, and pasting properties of oat bran were evaluated via Fourier transform infrared spectroscopy, scanning electron microscopy, colorimeter, and rapid viscosity analyzer. Results showed that the pulverization and extrusion did not produce new functional groups in the bran. However, both treatment methods could increase the content of soluble dietary fiber and degree of starch gelatinization, reduce oil-holding capacity, and increase water solubility index. Micro-pulverization increased the brightness and slowly digestible starch of the bran, reduced rapidly digestible starch (RDS), and enhanced the antioxidant capacity of oat bran. Conversely, extrusion reduced the brightness and antioxidant capacity of oat bran, increased RDS. And extrusion made the surface of the bran relatively flat and denatured the protein. This study provides a theoretical basis that enterprises involved in oat processing can refer to. According to different market needs, adopt appropriate processing methods to process oat bran in order to gain more oat bran products. Novelty impact statement Micro-pulverization and extrusion had a great influence on the physical and chemical properties of oat bran. Some indicators (such as anti-oxidation, color) had completely opposite results with two treatments. micro-pulverization did not change the functional groups of bran, did not affect its β-glucan content, but reduced its IDF content.